Typically, saw-teeth are required on the feedrolls used in lumber mills in order that cants (or squared-off logs which have two opposed planar surfaces) may be securely gripped for accuratedly positioned feeding into a band saw or saw cluster.
At present, in commercial operations, the saw-teeth are available in short strips of the various lengths. One or more strip lengths, depending on the length of the feed roll, are forced into a tight-fitting groove in the body of the feedroll by hammering or pinch clamping. The saw-teeth become blunted and ineffective after about six months to a year's use and require replacement. In order to replace the worn saw-teeth, it is necessary to first remove the feedroll from the machine. The technique for removing the inserts involves manually (or less commonly, pneumatically) chiselling the inserts out of the groove. Manual chipping is slow and inflicts damage to the groove. Pneumatic removal poses potential hazards to the operators due to the danger of flying metal fragments. Replacement of an insert can only be conducted by the conventional manual technique about three times before excessive damage to the groove has resulted. Usually at this point the saw-teeth strips are welded into the groove, for a final usage and upon dulling of these welded teeth the whole feedroll usually is discarded.
A search of the prior art has located the following patents of interest. U.S. Pat. No. 4,509,574 issued to W. M. Gaitten, teaches an improvement in a debarking machine wherein feed roll spikes having plus-shaped cutting edges are provided. R. A. Schmidt, in U.S. Pat. No. 4,385,650 describes an improved feed roll for logs which is provided with a plurality of radially extending trapezoidally shaped pyramids spaced circumferentially about the surface.
There still exists, therefore, the need for a system for removing and replacing saw-teeth strip inserts which would provide the following:
extension of the feedroll life, as replacement of the entire discarded feedroll per se is costly PA1 a speedier replacement, because the present method is both labour intensive and slow; PA1 reduction in potential injury to operators which can occur when replacement of the teeth is conducted in accordance with the prior art methods; and PA1 elimination of the requirement of removing the feed roll from the machine when tooth replacement is necessary. PA1 by elimination of the hammering in of the inserts and subsequent chipping out, no damage to the groove results and consequently the life of the feedroll is extended; PA1 by facilitating the replacement of the inserts, not only is there a significant saving in labour costs but operators are inclined to change the inserts more frequently and thereby run the feedrolls and mechanisms associated therewith more efficiently; and PA1 the safety hazards associated with the prior art methods have been lessened.